This disclosure relates to polyester compositions, and in particular to blends of polyesters with poly(ester-ether)copolymers, their methods of manufacture, and uses thereof.
Polyesters and polyester copolymers are well known thermoplastic polymers, and are useful for the manufacture of a wide variety of articles, from fibers to packaging. Poly(ester-ether)copolymers contain “hard blocks” (derived from the polyester units) and “soft blocks” (derived from the polyether units) that provide the polymer with elastomeric properties. Poly(ester-ether)copolymers are also thermoplastic, and thus processable by blow molding and injection molding. They have a number of advantageous properties, such as good resilience, low creep, resistance to impact, flex-fatigue resistance, and resistance to fuels, oils, and other organic solvents.
The properties of these materials can be modified by combining them with other polymers. Poly(ester-ether)copolymers often have relatively limited heat stability. In some applications, such as structural parts for automobiles, improved heat stability in combination with high notched Izod impact strength at low temperature is highly desirable. A number of blends of poly(ester-ether)copolymers with other polymer(s) have been described, for example in U.S. Pat. No. 4,904,748, GB 1431916 A, JP 09003309 A, WO 96/34055 A, WO 86/03049A, U.S. Pat. No. 5,541,244, U.S. Pat. No. 3,907,926, JP 11106617 A, and JP 58141236A. However these references do not have sufficient detail to disclose or teach one of ordinary skill in the art how to make compositions imparting sufficiently improved heat stability, particularly in combination with low temperature ductility properties. There accordingly remains a need in the art for thermoplastic compositions and articles based on poly(ester-ether)copolymers that are heat stable. It would further be advantageous if such compositions had high notched Izod impact strength at low temperature.